An 80-year-old man presents for treatment of a skin lesion situated on his right temple. The site was first noted several months ago by his caregiver and has been slowly increasing in size. The lesion has bled on numerous occasions. The patient’s medical history is positive for multiple actinic keratoses of his face and scalp, and a squamous cell carcinoma that was removed from his left cheek. Physical examination reveals a crusted plaque surrounded by erythema on his temple. Multiple actinic keratoses and solar lentigines are noted on his scalp and face.
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Squamous cell carcinoma (SCC) is a malignant neoplasm of keratinocytes that presents in up to 50% of all skin cancers.1,2 SCC may arise de novo or from an actinic keratosis. The yearly rate of conversion from actinic keratosis to SCC is estimated to be from <1% to 16%.3 SCC in situ progresses to invasive SCC once the tumor cells penetrate the basement cell membrane of the dermoepidermal junction.4 Metastatic disease is uncommon, and SCC has an overall mortality of approximately 2%.4
Risk factors for the development of SCC include advanced age, fair skin, chronic sun exposure, tobacco use, and immunosuppression; in recent years, a link to indoor tanning booths has been documented.5
Prevention of SCC includes avoiding ultraviolet light and tobacco. A prospective study indicates that sunscreen is effective in preventing actinic keratosis and SCCs.6 Retinoids, including vitamin A, also may have a chemoprotective role in the prevention of SCC, although the value of oral supplementation has yet to be determined.7
Stephen Schleicher, MD, is director of the DermDox Center for Dermatology, associate professor of medicine at Commonwealth Medical College, and clinical instructor of dermatology at Arcadia University and Kings College.
1. Que SKT, Zwald FO, Schmults CD Cutaneous squamous cell carcinoma: incidence, risk factors, diagnosis, and staging. J Am Acad Dermatol. 2018;78(2):237-247.
2. Rogers HW, Weinstock MA, Feldman SR, Coldiron BM. Incidence estimate of nonmelanoma skin cancer (keratinocyte carcinomas) in the U.S. population, 2012. JAMA Dermatol. 2015;151(10):1081-1086.
3. Glogau RG. The risk of progression to invasive disease. J Am Acad Dermatol. 2000;42(1 Pt 2):23-24.
4. Thompson AK, Kelley BF, Prokop LJ, Murad MH, Baum CL. Risk factors for cutaneous squamous cell carcinoma recurrence, metastasis, and disease-specific death: a systematic review and meta-analysis. JAMA Dermatol. 2016;152(4):419-428.
5. Lergenmuller S, Ghiasvand R, Robsahm TE, et al. Association of lifetime indoor tanning and subsequent risk of cutaneous squamous cell carcinoma. JAMA Dermatol. 2019;155(12):1350-1357.
6. Waldman RA, Grant-Kels JM. The role of sunscreen in the prevention of cutaneous melanoma and nonmelanoma skin cancer. J Am Acad Dermatol. 2019;80(2):574-576.
7. Kim J, Park MK, Li WQ, Qureshi AA, Cho E. Association of vitamin A intake with cutaneous squamous cell carcinoma risk in the United States. JAMA Dermatol. 2019;155(11):1260-1268.